Physiological electrode assembly for fast application

ABSTRACT

The present invention relates to a physiological recording electrode, and, more particularly, to an EEG (electroencephalography) recording electrode that can be used without the need for numerous steps in preparing the subject&#39;s skin and the electrode itself. The invention further relates to a surface feature or penetrator with a size and shape which that will not bend or break, which limits the depth of application, and/or anchors the electrode or other device during normal application; and a packaging system comprising a well and electrolytic fluid for maintaining a coating of said electrolytic fluid on the surface feature or penetrator.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. patent application Ser. No.14/701,944, filed on May 1, 2015, which issued into U.S. Pat. No.9,901,278, which claimed priority to U.S. patent application Ser. No.14/324,719, filed on Jul. 7, 2014, which issued into U.S. Pat. No.9,050,015, which claimed priority to U.S. patent application Ser. No.14/058,709, filed on Oct. 21, 2013, which issued into U.S. Pat. No.8,805,469, which claimed priority to U.S. patent application Ser. No.13/110,505, filed on May 18, 2011, which issued into U.S. Pat. No.8,594,763, and which claimed priority to U.S. Provisional Patent Appln.Ser. No. 61/348,151, which was filed on May 25, 2010.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a physiological recording electrode,and, more particularly, to an EEG (electroencephalography) recordingelectrode that can be used without the need for numerous steps inpreparing the subject's skin and the electrode itself. The inventionfurther relates to a surface feature or penetrator with a size and shapewhich that will not bend or break, which limits the depth ofapplication, and/or anchors the electrode or other device during normalapplication; and a packaging system comprising a well and electrolyticfluid for maintaining a coating of said electrolytic fluid on thesurface feature or penetrator.

2. Technology Review

Electrodes for measuring biopotential are used extensively in modernclinical and biomedical applications. These applications encompassnumerous physiological tests including electrocardiography (ECG),electroencephalography (EEG), electrical impedance tomography (EIT),electromyography (EMG) and electro-oculography (EOG). The electrodes forthese types of physiological tests function as a transducer bytransforming the electric potentials or biopotentials within the bodyinto an electric voltage that can be measured by conventionalmeasurement and recording devices.

In general, most commercial EEG electrodes for these applications todayare placed on the surface of the skin, which is a layered structureconsisting of the epidermis and the dermis. The dermis contains thevascular and nervous components. Further it is the part of the skinwhere pain has its origins. The epidermis, however, contains no vascularor nervous components and is made up of several layers, including theStratum basale or stratum germinativum, stratum spinosum, stratumgranulosum, stratum lucidum, and the stratum corneum.

The stratum corneum, the outermost layer of the skin, is the primarysource of high electrical impedance and, thus, this layer dramaticallyinfluences the biopotential measurements. The stratum corneum is verythin and uniform in most regions of the body surface ranging from 13-15μm with a maximum of about 20 μm. If the high impedance results from thestratum corneum can be reduced, a more stable electrode will result.Therefore with existing physiological electrodes the skin must beprepared prior to application when lower impedance is required.

The most common electrode preparation methods to avoid the highimpedance effects of the stratum corneum are: 1) shaving the hair fromthe skin; and either 2a) abrading the stratum corneum or 2b) using anelectrolytic gel. Electrodes requiring the use of an electrolytic gel orfluid are often referred to as “wet” electrodes. Hair is shaved from theskin to improve the contact between the electrodes and the skin surface.The goal of the abrasion of the stratum corneum is to reduce thethickness of (or remove) the stratum corneum (and therefore itselectrically insulating characteristics).

Drawbacks of abrading the skin are that the abraded area regeneratesdead cells fairly quickly (resulting in a limited time period for usingthe electrode), and if the abrasion is too deep the person canexperience pain. Additionally, electrolytic gels or fluids may beapplied to abraded surface to enhance the contact. Alternatively,electrolytic gels or fluids can be applied to the surface of the skindirectly. The electrolytic gel having a high concentration of conductiveions diffuses into the stratum corneum and improves its conductivity.Drawbacks observed with the use of electrolytic gels or fluids involvethe change of conductivity with time as the gels dry, discomfort (anitching sensation) at the patient's skin as a result of the gels drying,and the possibility of a rash due to an allergic reaction to theelectrolytic gels.

Further drawbacks of “wet” electrodes include skin preparation andstabilization of the electrode with respect to the skin surface. This isbecause movement of the electrode on the surface of the skin causes thethickness of the electrolytic layer (formed by the electrolytic gels orfluids) to change resulting in false variation in the measuredbiopotential. Some electrode designs have an adhesive backing to reducethe movement of the electrode on the skin surface; however, this featuredoes not eliminate completely the movement of the electrode with respectto the subject's skin. Another drawback is the length of time requiredto prepare the skin and apply the electrolytic gels or fluids prior tomeasurement of the biopotentials.

More recently, dry electrodes have been developed which eliminate manyof these limitations by foregoing the need for electrolytic fluids,gels, or colloids. For example, in Schmidt (U.S. Pat. No. 6,782,283) adry electrode containing a surface feature or penetrator is used topenetrate the stratum corneum of the skin and conduct a signal withoutthe aid of electrolytic fluid. The design of Schmidt is such that theelectrode's surface feature or penetrator(s) pierce, break, or createentry through the high impedance layers of the subject's skin, and thuscome in contact with the more electrically conductive layers whichfacilitates the transmission of biopotential signals.

The downside to Schmidt is that it teaches against the use ofelectrolytic fluid, gel or colloid at all. However, use of a dryelectrode with such electrolytic fluid, gel, or colloid unexpectedlyenhances the conductivity of biopotential signals being collected from asubject, particularly with weaker biopotential signals such as EEGsignals.

In view of the foregoing inherent disadvantages with presently availablewet and dry electrodes, it has become desirable to develop an electrodethat does not require skin preparation or the use of electrolytic gelsand overcomes the inherent disadvantages of presently available dryelectrodes.

SUMMARY OF THE INVENTION

The present invention relates to a physiological recording electrode orelectrode array, and, more particularly, to a physiological recordingelectrode or electrode array that can be used without the need fornumerous steps in preparing the subject's skin and the electrode itself.The electrode or electrode array preferably requires little or nopreparation of the subject's skin. The invention further relates to anelectrode or an array of electrodes where the surface of the electrodescomprises shapes or surface feature or penetrators that either penetratethrough the stratum corneum layer of the epidermis or create access tothe lower levels of the epidermis by cracking or breaking small areas ofthe stratum corneum to create entry or a via to lower layers of theepidermis. These features or penetrators preferably have a size andshape which prevents bending or breaking, which limits the depth ofapplication, and/or anchors the electrode or other device during normalapplication; and a packaging system comprising a well and electrolyticfluid providing a surface coating of electrolytic fluid on the surfacefeatures or penetrator.

The present invention, in its various embodiments, is intended toaddress many of the shortcomings of physiological electrodes currentlyavailable. Surface electrodes are an extremely important tool for themonitoring and recording of physiological signals. Therefore, it isimportant that these electrodes be capable of providing the clearest,cleanest signal possible and also to be easy to use to decrease the timeit takes to begin monitoring a subject's signal(s).

The present invention utilizes an electrolytic fluid, gel, or colloid tocoat the surface of the surface features or penetrators. Unlike previousphysiological recording devices requiring the use of such fluid, gels orcolloids, the present invention does not require the fluid, gel, orcolloid to be applied to the subject or patient separately and beforethe electrode is put into place. Thus, the present invention seeks toeliminate, or at least minimize, the length and degree of skinpreparation required to apply the electrode as well as the mess thataccompanies the use if separate fluids, gels, or colloids. Thiselectrolytic fluid preferably is such that will enhance the conductivityof biopotential signals from the subject to the recording or measuringdevice by reducing electrical impedance. Generally, electrolytic fluids,gels and colloids are designed with a high concentration of conductiveions, and as the fluid, gel or colloid diffuses into the subject'sstratum corneum it aids in conducting the biopotential signal throughthat layer. The present invention does not rely solely on theelectrolytic fluid, gel, or colloid to conduct the signal across thestratum corneum, but rather utilizes the increased conductivity totransfer the signal to the surface features or penetrators which alsopierce, break, or create entry through the stratum corneum. This has theadded benefit of minimizing the problems that arise through increasedthickness of the conductive layer due to the thickness of the fluid, gelor colloid layer as well as the potential drastic loss of conductivitywhen the fluid, gel, or colloid dries over time.

The present invention further utilizes a packaging base layer whichforms a base to which the electrode or electrode array can be attachedfor storage. This packaging base layer preferably comprises an uppersurface which the electrode or electrode array can attach to, and a wellto hold electrolytic fluid and into which the surface feature orpenetrator(s) can extend. This layer can be made of almost any type ofmaterial that does not react with the gels or electrolytic materialsbeing placed in the well. Preferably this layer is a plastic. Morepreferably different types of plastics can be used, including but notlimited to polyvinyl chloride, polystyrene, polyamide, polyethylene,polypropylene, polyurethane, Teflon, and the like; though it is notlimited only to plastics, and is designed to be used with othermaterials as well (i.e., metal, paper, rubber, and the like).Preferably, the materials used for the packaging base layer may becoated with a substance in order to allow for the various adhesiveportions of the device to be removable without losing their adhesivequality.

The adhesive may be of any variety known to those having skill in theart which are capable of securing the various portions of the presentinvention together for transportation and storage purposes, but thatallow the electrode or array to be removed from the package and thenplaced securely on the subject or patient without losing its adhesivecapabilities. The adhesive must be capable of being removed andreapplied to another surface without slipping, sliding, peeling off, orotherwise moving while in use.

An important aspect of many embodiments of the present invention is thesurface features or penetrators designed to pierce, break, or createentry through the tough, non-conductive outer layers of the skin. Manytypes of surface features are available for this purpose including butnot limited to ridges, columns, penetrators, anchors, epidermal stops,and combinations thereof. Preferably, there is at least one surfacefeature protruding from the electrode's lower surface. One of theimportant functions of the configuration of surface features is todisplace or move the hair, dead skin cells and/or detritus so that thesurface features can better collect the electrical biopotentialsgenerated by the body.

The ridge(s) as used in the present invention is preferably a long,narrow structure or elevation. The ridge(s) can have a variety of crosssections over a length. Examples of these cross sections include but arenot limited to a square, rectangle or trapezoid, a pointed surface likethat of a triangle, a domed surface like that of an arch or arc, a crosssection with a concave surface between to ridge lines forming the tworidge lines, some other unique cross-section or the like. The crosssection of the ridge extends for a length. The length of the ridge ispreferably substantially longer than the height or width of thecross-section of the ridge. The surface of the ridge away from thesubstrate, when applied to the skin surface, depresses, but does notneed to pierce the skin but anchors the electrode in place to preventmotion artifacts, to displace hair, dead skin cells and/or detritus, toincrease the surface area of the electrode in contact with the skin, andto be capable, in part, of transmitting an electric potential which canbe measured from the surface of the skin through the ridge.

A column(s) is another type of structure or elevation that can be usedin the present invention. A column(s) can have a variety of crosssections over a length. Examples of these cross sections include but arenot limited to a square, rectangle or trapezoid, a pointed surface likethat of a triangle, a domed surface like that of an arch or arc, a crosssection with a concave surface between two points (wherein the distancefrom the base to either point is greatest height of the column for thecross-section), some other unique cross-section or the like. The crosssection of the column like a ridge extends for a length. However, thewidth of the column is preferably in proportion to the height of thecross-section of the column, and more preferably shorter than the heightof the column. The surface of the column away from the substrate, whenapplied to the skin surface, depresses, and does not easily pierce theskin but anchors the electrode in place to prevent motion artifacts, todisplace hair, dead skin cells and/or detritus, to increase the surfacearea of the electrode in contact with the skin, and to be capable, inpart, of transmitting an electric potential which can be measured fromthe skin through the ridge.

A penetrator(s) is also a surface feature that can be used in thepresent invention. The penetrator(s) is sized and shaped for piercingthe stratum corneum or outer layer of the epidermis, and accessing thelower layers of the epidermis. The penetrator can take many shapesincluding but not limited to pyramidal, needle-like, triangular, or anyother shape that can be tapered to a point or tip. The surface of thepenetrator away from the substrate, when applied to the skin surface,readily pierces the skin, preferably anchors the electrode in place toprevent motion artifacts or any substantial movement, increases thesurface area of the electrode in contact with the skin and lower layersof the epidermis, and is capable, in part, of transmitting an electricpotential which can be measured from the skin and lower layers of theepidermis through the penetrator.

The epidermal stop(s), which can be used in the present invention, is astructure or elevation. Epidermal stops are structures of a particularheight with respect to the height of the penetrator(s) or other surfacefeatures so as to prevent the penetrator(s) or other surface featuressuch as columns and ridges from penetrating into the dermis of the skinor unduly distorting the surface of the skin, respectively, where theymight cause discomfort to the subject. An epidermal stop(s) may also beincorporated into a penetrator, ridge, column or like surface feature orcan be a separate surface feature. The epidermal stops may, however,have any shape known to those skilled in the art that would effectivelyprevent the penetrator(s) from entering the dermis of the skin, or frombeing applied to deeply. The epidermal stops are preferably applied inan array among the penetrators, therefore further minimizing inadvertentdeep penetration or over penetration by the penetrator(s) or minimizingsignificant distortion of the skin by other surface structures. If theepidermal stop is a separate surface feature or incorporated intoanother structure, preferably, the epidermal stop in combination with atleast one other surface feature or two structures with incorporatedepidermal stops create a detritus trough.

A detritus trough is the area interposed between adjacent surfacestructures or features. These troughs, when provided or naturallyoccurring in the design, allow for a more accurate placement of thesurface features by allowing for displacement of the hair and otherdetritus on the skin in these troughs. Preferably, the detritus troughsare sufficient in number and size to allow for placement of the deviceon skin with a significant amount of hair such as for example the scalpor the chest of a male subject. Detritus troughs are created to maximizethe area available for optimal device to skin contact, by improving theprobability that hair and other detritus will enter the troughs and notpreventing the surface features from either coming in contact with theskin or penetrating the skin. Thus detritus troughs may be parallel toone another, perpendicular to one another, or in any other orientationmade to improve the contact of the device with the skin of the subject.

An anchor(s), which can be used in the present invention is a structureor elevation that stabilizes the physiological device against asubject's skin. This stabilization further preferably prevents motionartifacts in the electrophysiological signal from the device, or anysubstantial movement. While the anchor can also be any of the structuresdescribed above, the anchor may also serve no other purpose except tostabilize or reduce movement of the device on the subject's skin. Theanchor(s) can have a variety of cross sections over a length asdescribed above for the various surface structures.

The present invention is designed to be used in connection with thecollection, conducting, measuring, and/or monitoring of biopotentialsignals. These biopotential signals may include electrocardiography(ECG), electrical impedance tomography (EIT), electromyography (EMG),electro-oculography (EOG), and most preferably electroencephalography(EEG).

One embodiment of the present invention involves a physiologicalrecording device comprising a packaging base layer comprising a wellcontaining a sponge and electrolytic fluid, and at least onephysiological recording electrode comprising an adhesive collar and aphysiological electrode comprising an upper and a lower surface, and atleast one surface feature protruding from the lower surface of thephysiological electrode, wherein the sponge holds the electrolytic fluidin contact with the at least one surface feature until the physiologicalrecording electrode is removed for placement on a subject.

Another embodiment of the present invention involves a physiologicalrecording device comprising a packaging base layer comprising a wellcontaining a colloid with electrolytic fluid, and at least onephysiological recording electrode comprising an adhesive collar and aphysiological electrode comprising an upper and a lower surface, and atleast one surface feature protruding from the lower surface of thephysiological electrode, wherein the colloid holds the electrolyticfluid in contact with the at least one surface feature until thephysiological recording electrode is removed for placement on a subject.

Yet another embodiment of the present invention involves a physiologicalrecording device comprising a packaging base layer comprising a wellcontaining a sponge with electrolytic fluid, and at least onephysiological recording electrode comprising an adhesive collar and aphysiological electrode comprising an upper and a lower surface, and atleast two surface features protruding from the lower surface of thephysiological electrode, wherein the sponge holds the electrolytic fluidin contact with the at least two surface features until thephysiological recording electrode is removed for placement on a subject.

It is to be understood that both the foregoing general description andthe following detailed description are merely exemplary of theinvention, and are intended to provide an overview or framework forunderstanding the nature and character of the invention as it isclaimed. It is understood that many other embodiments of the inventionare not directly set forth in this application but are none the lessunderstood to be incorporated by this application. The accompanyingdrawings are included to provide a further understanding of theinvention, and are incorporated in, and constitute a part of, thisspecification. The drawings illustrate various embodiments of theinvention and together with the description serve to explain theprinciples and operation of the many embodiments of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Aerial and side views of one embodiment of electrodes packagedin an electrolytic gel well where the well is attached to the bottom ofa separator.

FIG. 2. Cross-sectional view of an electrode with the surface feature orpenetrators resting in a gel well attached to a separator.

FIG. 3. Cross-sectional view of an electrode removed from the packagingwith electrolytic fluid coating the surface feature or penetrator(s).

FIG. 4. Cross-sectional view of gel well with separator.

FIG. 5. Cross-sectional view of an electrode in the process of beinglifted and separated from the packaging base layer, which is formed by agel well attached to the bottom of a separator, with a coating ofelectrolytic fluid remaining on the surface feature or penetrator(s) ofthe electrode.

FIG. 6. Cross-sectional view of the layers of skin being and withsurface feature or penetrators of an electrode piercing those layers.

FIG. 7. Aerial and side views of one embodiment of electrodes packagedin an electrolytic gel well where the well is molded into the packagingbase layer.

FIG. 8. Cross-sectional view of an electrode with surface feature orpenetrators in a gel well that is molded into the packaging layer.

FIG. 9. Cross-sectional view of a gel well molded into the packagingbase layer.

FIG. 10. Cross-sectional view of an electrode in the process of beinglifted and separated from the packaging base layer, which is formed by agel well molded into the packaging base layer, with a coating ofelectrolytic fluid remaining on the surface feature or penetrator(s) ofthe electrode.

FIG. 11. Cross-sectional view of an electrode comprising various surfacefeatures including penetrators, anchors and epidermal stops.

FIG. 12. Cross-sectional view of an electrode comprising various surfacefeatures including penetrators, ridges and columns.

DETAILED DESCRIPTION OF THE DRAWINGS

Various embodiments of the methods of the present invention include oneor more of the following components, and variations thereof. One ofthese components includes a packaging base layer comprising a wellcontaining a sponge and electrolytic fluid. The packaging base layeritself provides a foundation for the electrode to be attached to orrested upon. The packaging base layer is preferably made of a material,and of dimensions, that allow it to be flexible. This packaging baselayer can be made of any material that will allow the adhesive collar ofthe electrode to adhere to its surface while still allowing it to peelaway. Further, the wells may be created by any number of methodsincluding, but not limited to, drilling them into the packaging baselayer, grinding them out of the packaging base layer, creating theentire packaging base through various methods of molding, and the like.Preferably, the packaging base is made of a cheap material, such asplastics, to keep manufacturing costs low. Specific plastic fabricatingtechniques that could be used to create the packaging base include, butare not limited to, extrusion, injection molding, compression molding,reaction injection molding, vacuum forming, and the like.

One embodiment of the present invention involves a packaging base layerthat is made of a thin packaging base layer with a gel well attached tothe lower surface. This packaging base layer is preferably made of amaterial, and of dimensions that allow it to be flexible. This packagingbase layer can be made of any material that will allow the adhesivecollar of the electrode to adhere to its surface while still allowing itto peel away (i.e. plastics as described above, metal, and the like).This layer can be made of almost any type of plastic, including but notlimited to polyvinyl chloride, polystyrene, polyamide, polyethylene,polypropylene, polyurethane, Teflon, and the like, or other materialssuch as metals. Preferably, the packaging base layer is constructed ofsuch a material as to be disposable. In other words, once the product isopened, and the physiological recording electrodes removed to be placedon a subject or patient, the user should preferably be able to discardthe packaging base layer in the trash, and not need to follow anyspecial or particular disposal instructions (i.e., biohazardprocedures). The well can similarly be made of any such material. Forthis packaging method, an aperture or hole must be cut in the packagingbase layer and the gel well attached to the lower surface aligned withthe hole in the packaging base layer. This creates the well where mediumcontaining the electrolytic fluid can be placed.

The medium containing the electrolytic fluid can be any porous material,such as to a sponge, or colloidal suspension placed inside the well forpurposes of holding electrolytic fluid and keeping said fluid in contactwith the surface feature or penetrators of the electrode when theelectrode is affixed to the upper surface of the packaging base layer.When the electrode is affixed as such, the surface feature orpenetrators extend through the aperture and into the sponge or colloidwhere they are submersed in the electrolytic fluid and become coatedwith same. The electrolytic fluid is generally of sufficient viscositythat when the electrode is removed from the packaging layer, a coatingof the electrolytic fluid remains on the surface of the surface featureor penetrators, thereby enhancing their conductive properties for thepurpose of transmitting biopotential signals from the subject's body tothe monitoring equipment.

Another component of various embodiments of the present inventionincludes at least one physiological recording electrode comprising anadhesive collar, an upper and lower surface, and a connection node. Theadhesive collar is preferably constructed of material that is capable oftransferring moisture to avoid sweating when attached to the subject'sskin, thus preventing slipping of the electrode. The connection node isa piece that may be molded into a single piece with the rest of theelectrode body or a separate piece assembled onto the electrode body.The node is preferably molded or attached to the upper surface of theelectrode such that when the electrode is attached to a subject orpatient, the connection node extends up away from the subject. The nodecreates a connection point for the electrode leads which are connectedto the appropriate monitoring equipment.

Preferably, the physiological recording electrode comprises at least onesurface feature or surface feature or penetrator protruding from thelower surface of the physiological electrode that is capable ofpiercing, breaking, or creating entry through the stratum corneum layeror outer layer of a subject's skin. The surface feature(s) or surfacefeature or penetrator(s) may or may not be coated with a conductivematerial, such as silver, gold, or other material such as silver-silverchloride. This coating preferably is one that maintains or is likely tomaintain an electrical attraction to electrolytic fluids that may beused to further coat the surface of the surface feature or penetrator tofacilitate the transmission of physiological signals.

Now referring to the FIGS. 1-10, FIG. 1 is both an aerial and side viewof one embodiment of the present invention wherein at least onephysiological electrode 7 is packaged in such a manner that the at leastone surface feature or penetrator 21 extends into a well 9 containing orholding electrolytic fluid 23. The electrolytic fluid 23 may be infusedinto a porous material 27 such as a sponge 27, it may be dispersed intoa colloidal suspension 27 with some dispersion medium (not shown), itmay be a viscous fluid with properties described herein contained by thewell, or other method currently known or developed in the future. Thepackaging base layer 1 provides a substrate comprising an upper surface3 and a lower surface 5. Physiological recording electrodes or arrayscomprising electrodes 7 (comprising at least a physiological recordingelectrode and an adhesive collar 15) are attached to the upper 3 surfacevia the attached adhesive collar 15. Although the figure depicts foursuch electrodes 7, the two center electrodes comprise a two electrodearray, whereas the two outside electrodes 7 are individual electrodes.The upper surface 3 preferably comprises a smooth surface which allowsfor temporary adhesion of the electrode's 7 adhesive collar 15, but alsoallows the electrodes or electrode array to be removed without loss ofthe adhesive quality for secure attachment of the electrodes andelectrode array to a subject or patient. The electrode(s) 7 are placedon the packaging layer 1 in such a manner that the electrode 7 isaligned with an aperture (not shown) through the packaging layer and atleast one surface feature or penetrator 21 on the electrode extends intothe packaging well 9. The well 9 preferably contains a sponge or otherporous material 27 infused with electrolytic fluid 23, or a colloidalsuspension 27 containing electrolytic fluid 23. The surface feature orpenetrators 21 thereby remain bathed in the electrolytic fluid 23throughout their time in the packaging regardless of how they arestored, and are thus coated with said fluid when removed from thepackaging layer 1 and are ready for application onto a subject. Callout17 is depicted in greater detail in FIGS. 2-5, and depicts variousfeatures of the present invention.

FIG. 2 is a cross-sectional view of one embodiment of the presentinvention and callout 17 from FIG. 1 wherein an electrode 7 is attachedto a packaging system comprising a base layer 1 with an electrolyticfluid 9 well attached to, or formed in, the bottom of the base layer.

In this particular embodiment, the packaging base layer 1 comprises athin layer of material such as plastic. This layer can be made of almostany type of material that does not react with the gels or electrolyticmaterials being placed in the well. Preferably this layer is a plastic.More preferably different types of plastics can be used, including butnot limited to polyvinyl chloride, polystyrene, polyamide, polyethylene,polypropylene, polyurethane, Teflon, and the like; though it is notlimited only to plastics, and is designed to be used with othermaterials as well (i.e., metal, paper, rubber, and the like). The uppersurface 3 of the packaging base layer 1, acts as an attachment surfacefor the electrode 7. This upper surface 3 preferably is smooth andnon-binding such that allows the electrode assembly to be removed fromthe surface without sticking and without loss of the adhesive substanceused to attach the electrode to a subject or patient. The lower surface5 of the packaging base layer can act as an attachment surface for theelectrolytic fluid well 9. The lower surface 5 of the packaging baselayer 1 preferably is able to maintain a strong bond between itself andthe well's adhesive edges to avoid separation and prevent leakage orloss of electrolytic fluid. The packaging base layer 1 furtherpreferably comprises apertures or holes (not labeled) through the entirelayer 1 such that the electrode 7 attached to the upper surface 3 andthe electrolytic fluid well 9 attached to the lower surface 5 are inalignment, and the electrode, with at least one surface feature orpenetrator 21, may extend through said aperture or hole to be held incontact with the electrolytic fluid 23 or colloid 27 contained in thewell 9.

The electrode assembly preferably comprises at least an adhesive collar15, an electrode body 19, a connection node 17 which is formed with orattached to the electrode body, and at least one surface feature orpenetrator 21, capable of piercing or breaking the stratum corneum 35 ofa subject's skin. The adhesive collar 15 preferably comprises a materialsuch as a foam material or a breathable polymer which providesflexibility as well as support, and an adhesive layer (not shown) whichmay consist of a very thin coating of said adhesive on the bottomsurface of the lower or outer portion of the collar 15 and which is usedto attach the electrode assembly first to the package 1, and thensubsequently to a subject's skin or body. Also preferably, the electrodeassembly contains at least one surface feature or penetrator 21 as partof the electrode body 19 which is capable of piercing or creating anopening in a stratum corneum 35 layer or outer layer of a subject'sskin. This electrode is then placed in contact with the upper surface 3of the packaging base layer 1 in such a manner that the electrode body19 and the at least one surface feature or penetrator 21 are in linewith an aperture or hole (not labeled) through the base layer and the atleast one surface feature or penetrator 21 extends through the apertureor hole and is held in place by virtue of the adhesive on the adhesivecollar 15.

The electrolytic fluid well preferably comprises at least a pocket orwell 9 attached to the lower surface 5 of the packaging layer 1 with anadhesive (not shown), and a medium 27 for holding electrolytic fluidwhich may comprise a sponge, a colloidal suspension, or some otherdevice capable of holding the fluid in contact with the surface featureor penetrator 21. In the present embodiment, the electrolytic fluid well9 may be created by means of an adhesive collar that is either similaror identical to the adhesive collar 15 used to attach the electrodeassembly to the packaging layer 1 and the subject or patient. If theelectrolytic fluid 23 is infused into a sponge 27, the sponge may be anyporous material placed inside the well 9 for purposes of absorbing andholding electrolytic fluid. If the electrolytic fluid 23 is dispersedinto a colloidal suspension or disc 27, the continuous phase, ordispersion medium can be of any type that will readily hold theparticular electrolytic fluid being used while allowing the at least onesurface feature or penetrator 21 of the electrode to be held in contactwith the medium 27 and coated by the electrolytic fluid 23. The adhesiveused to attach the fluid well to the lower surface of the packaginglayer 5 preferably is a permanent adhesive and is different from thatused to attach the electrode 7 to the upper surface 3. Similar to theelectrode 7, the electrolytic fluid well 9 is attached to the lowersurface 5 in such a manner that the well is aligned with the aperture orhole (not labeled) in the packaging base layer 1. As such, the at leastone surface feature or penetrator 21 of the electrode 7 extends throughthe aperture and into the electrolytic well 9, more specifically intothe electrolytic fluid medium 27, where it comes into contact with theelectrolytic fluid 23 maintaining a coating of said fluid on the surfacefeature or penetrator 21.

Alternatively, the electrolytic fluid well 9 may comprise a multiplepiece system (not shown) in which an open adhesive collar (not shown) isused and which requires the placement of a base layer over the openingnot in contact with the packaging base layer to prevent loss or leakageof electrolytic fluid. Similarly, a multiple piece system as describedcould be used with the electrode assembly as well, where the base layeris attached to the opening of the electrode adhesive collar 15 and isfurther used to connect that collar to the electrode body 19.

The surface feature(s) or penetrator(s) 21 of the electrode body remainin constant or regular contact with electrolytic fluid 23 throughout thetime the electrode 7 remains attached to the package 1. The presentinvention is designed so that when the electrode 7 is removed from thepackage 1, the at least one surface feature or penetrator 21 maintains acoating of the electrolytic fluid 23 and no external application ofelectrolytic fluid is necessary. This eliminates an extra and uncertainstep from the application process.

In many cases, the at least one surface feature or penetrator 21 iscoated in some conductive substance, such as a silver/silver chloride,which facilitates the conduction of electrical biopotential signals fromthe subject or patient to the monitoring equipment. Preferably, theelectrolytic fluid used is designed to maintain a surface attraction tothe conductive coating on the penetrator(s) to aid in the electrolyticfluid remaining 23 attached or attracted to the surface of the surfacefeature(s) or penetrator(s) 21.

FIG. 3 is a cross-sectional view of one embodiment of the presentinvention wherein an electrode is removed from the packaging system.

The electrode assembly preferably comprises at least an adhesive collar15, an electrode body 19, a connection node 17 which is attached to theelectrode body 19, and at least one surface feature or penetrator 21,capable of piercing the stratum corneum 35 of a subject's skin. Theadhesive collar 15 preferably comprises a material such as a foam rubberor sponge-like material which provides flexibility as well as support,and an adhesive layer (not shown) which may consist of a very thincoating of said adhesive on the lower or outer portion of the collar 15and which is used to attach the electrode assembly first to the uppersurface 3 of the package 1, and then subsequently to a subject's skin orbody (not shown). Also preferably, the electrode assembly contains atleast one surface feature or penetrator 21 as part of the electrode body19 which is capable of piercing or creating an opening in a stratumcorneum 35 layer or outer layer of a subject's skin. This electrodeassembly is then placed in contact with the upper surface 3 of thepackaging base layer 1 in such a manner that the electrode body 19 andthe at least one surface feature or penetrator 21 are in line with anaperture or hole (not labeled) through the base layer 1 and the at leastone surface feature or penetrator 21 extends through the aperture orhole and is held in place by virtue of the adhesive on the adhesivecollar 15.

The surface feature or penetrator(s) 21 of the electrode body 19 remainin constant contact with electrolytic fluid 23 throughout the time theelectrode assembly remains attached to the package 1. The presentinvention is designed so that when the electrode assembly is removedfrom the package, the at least one surface feature or penetrator 21maintains a coating of the electrolytic fluid 23 and no externalapplication of electrolytic fluid is necessary. This eliminates an extrastep from the application process.

Additionally, the present invention may be used with dry electrodeswhich do not require the application of electrolytic fluid. In thesecases, the present invention allows the surface feature or penetrator(s)to maintain a slight, thin coating of fluid 23 which further aids theconduction of signals.

In many cases, the at least one surface feature or penetrator 21 iscoated in some conductive substance (not shown), such as a silver/silverchloride, which facilitates the conduction of electrical biopotentialsignals from the subject or patient to the monitoring equipment.Preferably, the electrolytic fluid 23 used is designed to maintain asurface attraction to the conductive coating (not shown) on the surfacefeature or penetrator(s) 21 to aid in the electrolytic fluid 23remaining attached or attracted to the surface of the surface feature orpenetrator(s) 21.

FIG. 4 is a cross-sectional view of one embodiment of the presentinvention wherein an electrolytic fluid well is attached to a packagingsystem comprising a base layer and an aperture or hole.

The electrolytic fluid well preferably comprises at least a pocket orwell 9 attached to the lower surface 5 of the packaging layer 1 with anadhesive (not shown), and a medium for holding electrolytic fluid 27which may comprise a sponge, a colloidal suspension, or some other meansof holding the fluid. In the present embodiment, the electrolytic fluidwell 9 may be created by means of an adhesive collar that is eithersimilar or identical to the adhesive collar 15 used to attach theelectrode assembly to the packaging layer 1 and the subject or patient.If the electrolytic fluid 23 is infused into a sponge, said sponge maybe any porous material placed inside the well for purposes of absorbingand holding electrolytic fluid 23. If the electrolytic fluid 23 isdispersed into a colloidal suspension, the continuous phase, ordispersion medium can be of any type that will readily absorb and holdthe particular electrolytic fluid 23 being used while allowing the atleast one surface feature or penetrator 21 of the electrode assembly topenetrate the medium 27 and become coated by the electrolytic fluid 23.The adhesive (not shown) used to attach the fluid well 9 to the lowersurface 5 of the packaging layer 1 can be the same or similar as thatused to attach the electrode assembly to the upper surface 3. Similar tothe electrode assembly, the electrolytic fluid well 9 is attached to thelower surface 5 in such a manner that the well is aligned with theaperture or hole (not labeled) in the packaging base layer 1. As such,the at least one surface feature or penetrator 21 of the electrodeassembly extends through the aperture and into the electrolytic well 9,more specifically into the electrolytic fluid medium 27, where it comesinto contact with the electrolytic fluid 23 maintaining a coating ofsaid fluid.

Alternatively, the electrolytic fluid well may comprise a multiple piecesystem (not shown) in which an open adhesive collar 15 is used and whichrequires the placement of a base layer (not shown) over the opening notin contact with the packaging base layer 1 to prevent loss or leakage ofelectrolytic fluid 23. Similarly, a multiple piece system as describedcould be used with the electrode assembly as well, where the base layeris attached to the opening of the electrode adhesive collar 15 and isfurther used to connect that collar to the electrode body 19.

The entire packaging portion depicted in the current figure is designedto be disposable. However, depending on the purposes for which theelectrode or electrode array is being used, the packaging layer depictedhere could be retained during monitoring in case the electrolytic fluid23 needs to be reapplied to the surface of the surface feature orpenetrator(s) 21. In such a situation, the electrode could be removedfrom the subject and pressed back onto the packaging system in a mannersuch that the surface feature or penetrator(s) 21 extend back into themedium 27 containing the fluid 23 thereby coating the surface of thesurface feature or penetrator(s) 21 with fresh electrolytic fluid 23.The electrode could then be reapplied to the subject or patient forcontinued monitoring of the physiological signal.

FIG. 5 is a cross-sectional view of the electrode assembly in theprocess of being removed from the packaging system comprising the baselayer 1, electrolytic fluid well 9, and the medium 27 containing theelectrolytic fluid 23.

One side of the electrode assembly has been detached from the packagingbase layer 1 while the other side remains attached. The at least onesurface feature or penetrator 21 lifts up and out of the medium 27 andremains coated with the electrolytic fluid 23 which is contained in themedium 27. As previously described, the medium 27 may be a sponge, acolloidal suspension, or some other medium capable of holding anelectrolytic fluid 23 and also of allowing the at least one surfacefeature or penetrator 21 to enter said medium 27 and come in contactwith the electrolytic fluid 23.

FIG. 6 is a cross-sectional cut-away view of the typical epidermis layerof a subject's or patient's skin. The epidermis generally consists ofthe five outer layers of the skin, including the stratum corneum 35, thestratum lucidum 36, stratum granulosum 37, stratum spinosum 38, andstratum basale 39. This figure depicts the electrode, comprising theelectrode body 19 and the surface feature or penetrator(s) 21, piercingthrough the outer layers of the skin, most importantly the stratumcorneum 35. The stratum corneum 35 presents the greatest barrier toconductivity of physiological signals. The surface feature orpenetrator(s) 21 pierce, break, or create entry through the stratumcorneum 35 to the less electrically resistant layers and therebycollects and transmits a stronger, clearer physiological signal to themonitoring equipment (not shown). The surface feature or penetrator(s)21 remain coated in electrolytic fluid 23 when removed from thepackaging system thus further facilitating the conduction of thephysiological signal to the monitoring equipment.

FIG. 7 is both an aerial and side view of one embodiment of the presentinvention wherein at least one physiological electrode 7 is packaged insuch a manner that the at least one surface feature or penetrator 21extends into a well 9 containing or holding electrolytic fluid 23. Theelectrolytic fluid 23 may be infused into a porous material 27 such as asponge 27, it may be dispersed into a colloidal suspension 27 with somedispersion medium (not shown), it may be a viscous fluid with propertiesdescribed herein contained by the well, or other method currently knownor developed in the future. The packaging base layer 33 provides asubstrate comprising an upper surface 3. Physiological recordingelectrodes or arrays comprising electrodes 7 (comprising at least aphysiological recording electrode and an adhesive collar 15) areattached to the upper surface 3 via the attached adhesive collar 15.Although the figure depicts four such electrodes 7, the two centerelectrodes comprise a two electrode array, whereas the two outsideelectrodes 7 are individual electrodes. The upper surface 3 preferablycomprises a smooth surface which allows for temporary adhesion of theelectrode's 7 adhesive collar 15, but also allows the electrodes orelectrode array to be removed without loss of the adhesive quality forsecure attachment of the electrodes and electrode array to a subject orpatient. The electrode(s) 7 are placed on the packaging layer 33 in sucha manner that the electrode 7 is aligned with an aperture (not shown)through the packaging layer and at least one surface feature orpenetrator 21 on the electrode extends into the packaging well 9. Thewell 9 preferably contains a sponge or other porous material 27 infusedwith electrolytic fluid 23, or a colloidal suspension 27 containingelectrolytic fluid 23. The surface feature or penetrators 21 therebyremain bathed in the electrolytic fluid 23 throughout their time in thepackaging regardless of how they are stored, and are thus coated withsaid fluid when removed from the packaging layer 33 and are ready forapplication onto a subject. Callout 31 is depicted in greater detail inFIGS. 8-10, and depicts various features of the present invention.

FIG. 8 is a cross-sectional view of one embodiment of the presentinvention wherein an electrode assembly is attached to a packagingsystem comprising a base layer further comprising an electrolytic fluidwell.

In this particular embodiment, the packaging base layer 33 comprises abase of material such as plastic. This layer can be made of almost anytype of plastic, including but not limited to polyvinyl chloride,polystyrene, polyamide, polyethylene, polypropylene, polyurethane,Teflon, and the like; though it is not limited only to plastics, and isdesigned to be used with other materials as well (i.e., metal, paper,rubber, and the like). The upper surface 3 of the packaging base layer33, acts as an attachment surface for the electrode assembly. This uppersurface 3 preferably is smooth and non-binding such that allows theelectrode assembly to be removed from the surface without sticking andwithout loss of the adhesive substance (not shown) used to attach theelectrode assembly to surfaces. In the present embodiment, the packagingbase layer 33 itself comprises a solid piece which can be manufacturedin any applicable manner (i.e., for plastic: injection molding,extrusion, and the like). The packaging base layer 33 further preferablycomprises at least one depression, crater, hollow, or other such featurewhich creates a well (not labeled) such that the electrode assemblyattached to the upper surface 3 can extend past the upper surface 3 ofthe base layer 33 and into said package.

The electrode assembly preferably comprises at least an adhesive collar15, an electrode body 19, a connection node 17 which is attached to theelectrode body 19, and at least one penetrator 21. The adhesive collar15 preferably comprises a material such as a foam rubber or sponge-likematerial which provides flexibility as well as support, and an adhesivelayer (not shown) which may consist of a very thin coating of saidadhesive on the lower or outer portion of the collar. Also preferably,the electrode assembly contains at least one penetrator 21 as part ofthe electrode body 19 which is capable of piercing or creating anopening in a stratum corneum layer 35 or outer layer of a subject'sskin. This electrode assembly is then placed in contact with the uppersurface 3 of the packaging base layer 33 in such a manner that theelectrode body 19 and the at least one penetrator 21 are in line with awell 9 in the base layer and the at least one penetrator 21 extends intothe well 9 and is held in place by virtue of the adhesive (not shown) onthe adhesive collar 15.

The electrolytic fluid well preferably comprises at least a pocket orwell 9 bored, molded, or otherwise formed into the packaging base layer33, and a medium 27 for holding electrolytic fluid which may comprise asponge, a colloidal suspension, or some other device capable of holdingthe fluid in contact with the surface feature or penetrator 21. If theelectrolytic fluid 23 is infused into a sponge 27, the sponge may be anyporous material placed inside the well 9 for purposes of absorbing andholding electrolytic fluid. If the electrolytic fluid 23 is dispersedinto a colloidal suspension or disc 27, the continuous phase, ordispersion medium can be of any type that will readily hold theparticular electrolytic fluid being used while allowing the at least onesurface feature or penetrator 21 of the electrode to be held in contactwith the medium 27 and coated by the electrolytic fluid 23. When theelectrode or electrode array 7 is attached to the upper surface 3 of thepackaging base layer 33, the at least one surface feature or penetrator21 of the electrode 7 extends through the aperture and into theelectrolytic well 9, more specifically into the electrolytic fluidmedium 27, where it comes into contact with the electrolytic fluid 23maintaining a coating of said fluid on the surface feature or penetrator21.

FIG. 9 The electrolytic fluid well preferably comprises at least apocket or well 9 bored, molded, or otherwise formed into the packagingbase layer 33, and a medium 27 for holding electrolytic fluid which maycomprise a sponge, a colloidal suspension, or some other device capableof holding the fluid in contact with the surface feature or penetrator21. If the electrolytic fluid 23 is infused into a sponge 27, the spongemay be any porous material placed inside the well 9 for purposes ofabsorbing and holding electrolytic fluid. If the electrolytic fluid 23is dispersed into a colloidal suspension or disc 27, the continuousphase, or dispersion medium can be of any type that will readily holdthe particular electrolytic fluid being used while allowing the at leastone surface feature or penetrator 21 of the electrode to be held incontact with the medium 27 and coated by the electrolytic fluid 23.

The entire packaging portion depicted in the current figure is designedto be disposable. However, depending on the purposes for which theelectrode or electrode array is being used, the packaging layer depictedhere could be retained during monitoring in case the electrolytic fluid23 needs to be reapplied to the surface of the penetrator(s) 21. In sucha situation, the electrode could be removed from the subject and pressedback onto the packaging system in a manner such that the penetrator(s)21 extend back into the medium 27 containing the fluid 23 therebycoating the surface of the penetrator(s) 21 with fresh electrolyticfluid 23. The electrode could then be reapplied to the subject orpatient for continued monitoring of the physiological signal.

FIG. 10 is a cross-sectional view of the electrode assembly in theprocess of being removed from the packaging system comprising the baselayer 33, electrolytic fluid well 9, and the medium 27 containing theelectrolytic fluid 23.

One side of the electrode assembly has been detached from the packagingbase layer 33 while the other side remains attached. The at least onepenetrator 21 lifts up and out of the medium 27 and remains coated withthe electrolytic fluid 23 which is contained in the medium 27. Aspreviously described, the medium 27 may be a sponge, a colloidalsuspension, or some other medium capable of holding an electrolyticfluid 23 and also of allowing the at least one penetrator 21 to entersaid medium 27 and come in contact with the electrolytic fluid 23.

FIG. 11 is a cross-sectional view of one embodiment of an electrodecomprising various surface features including penetrators, anchors andan epidermal stop. The depicted electrode embodiment specifically isportrayed comprising penetrators 21, an epidermal stop 44, and anchors46, all as described herein.

FIG. 12 is a cross-sectional view of one embodiment of an electrodecomprising various surface features including penetrators, a ridge and acolumn. The depicted electrode embodiment specifically is portrayedcomprising penetrators 21, a ridge 48, and a column 50, all as describedherein.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the present inventionwithout departing from the spirit and scope of the invention. Thus, itis intended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

The invention claims:
 1. A physiological recording device comprising: apackaging base layer comprising a well containing an electrolytic fluid,gel or colloid; and at least one EEG physiological recording electrode,the at least one EEG physiological recording electrode comprising anupper and a lower surface, and at least one surface feature protrudingfrom the lower surface of the EEG physiological electrode, wherein theelectrolytic fluid, gel or colloid are at least in contact with the atleast one surface feature of the EEG physiological recording electrodeuntil the at least one surface feature of the physiological recordingelectrode is removed from the well for placement on a subject.
 2. Thephysiological recording device of claim 1, wherein the at least onesurface feature of the at least one EEG physiological electrode isselected from the group of surface features consisting of penetrators,ridges, columns, anchors and epidermal stops.
 3. A physiologicalrecording device comprising a packaging base layer comprising a wellcontaining a colloidal suspension; and at least one EEG physiologicalrecording electrode, the at least one EEG physiological recordingelectrode comprising an upper and a lower surface, and at least onesurface feature protruding from the lower surface of the EEGphysiological recording electrode wherein the colloidal suspension is atleast in contact with the at least one surface feature of the EEGphysiological recording electrode until the at least one surface featureof the EEG physiological recording electrode is removed from the wellfor placement on a subject.
 4. The physiological recording device ofclaim 3, wherein the at least one surface feature of the at least oneEEG physiological electrode is selected from the group of surfacefeatures consisting of penetrators, ridges, columns, anchors andepidermal stops.
 5. A physiological recording device comprising: apackaging base layer comprising at least one well containing a colloidalsuspension or a porous material with electrolytic fluid or gel infusedin the porous material; and at least one EEG physiological recordingelectrode, the at least one EEG physiological recording electrodecomprising an upper and a lower surface, and at least one surfacefeatures protruding from the lower surface of the EEG physiologicalrecording electrode, wherein the sponge holds the electrolytic fluid incontact with the at least one surface features of the EEG physiologicalrecording electrode until the at least one surface feature of thephysiological recording electrode is removed from the well for placementon a subject.
 6. The physiological recording device of claim 5, whereinthe at least one surface feature is from the group of surface featuresconsisting of penetrators, ridges, columns, anchors and epidermal stops.